Letting It ‘Mellow if It’s Yellow’ Is Way Better for the Environment

And it’s hygienic, too

“If it’s yellow, let it mellow!” Or as they say in the Caribbean, “In the land of sun and fun, we do not flush for number 1.” It’s a maxim held dear by the selective flusher, and despite what cleaning product commercials might have you believe, the practice isn’t necessarily uncouth.

But is it as gross as your partner, spouse or roommate claims?

First, let’s break down the “yellow” in question (aka urine). Essentially, it’s water mixed with the substances excreted by your kidneys: These include nitrogen, phosphorus and potassium; salts; and traces of any pharmaceuticals you happen to be taking, to name a few — more than 3,000 chemical compounds in all. And though most of us grew up hearing that urine is sterile, at least one recent study claims that there’s actually some bacteria in it after all.

That said, it’s pretty unlikely that you’ll catch anything from the liquid contents of your toilet. For one, you’re (presumably) not actually touching the inside of the bowl, and while BYU researchers have documented the artfully named phenomenon of “male splashback,” as long as everyone washes their hands after a visit to the men’s room, you should be just fine. In terms of spreading germs, in fact, it’s actually flushing that’s more likely to do this than anything else, since it can cause germs to be fired up to six feet out of the bowl to drift throughout your bathroom.

So if selective flushing isn’t technically unhygienic, is it, for want of a better word, dirty? If you’re healthy and well-hydrated — and you don’t much care for asparagus — your pee shouldn’t have a strong color or odor, and if you clean your toilet regularly, you shouldn’t be seeing any strange buildup in the bowl, so going a few rounds between flushes won’t be too unpleasant.

Another major pro is that not flushing is a significant water-saver. A standard throne uses 1.6 gallons of water per flush, so if you flush three times a night, that’s 4.8 gallons down the drain. But if you flush every third time, you’re saving 3.2 gallons of water per night, 22.4 gallons per week, 89.6 gallons per month and 1,075 gallons a year — that’s enough to fill a small tanker truck over the next five years.

If you like the idea of saving water but find the thought of a toilet steeped in stale urine gives you the creeps, you also could try Why Flush, a citrus-scented “toilet water neutralizer” liquid that claims to “neutralize” urine while dyeing the water a pleasing blue-green color.